The search: "life tables" "age 80" longevity in firstgov.gov got 46 hits, including a number of CDC pages.
The National Center for Health Statistics links to United States Life Tables from the Public Health Service. The most recent is the Center for Disease ControlNational Vital Statistics Reports, vol. 54 no. 14, April 19,2006. Page 3 of this has "Table B: Number of survivors by age, out of 100,000 born alive, by race and sex: United States 2003". This table gives figures for every 5 years, up to age 100. The total for all people age 80 is 52,741 (that is, about 53%); for all US whites 53,816 (about 54%), and all blacks 40,054 (40%). The spread between male and female is quite striking – 15% more white women than white men, nearly 18% more black women than black men, and almost exactly 15% more women in all races combined. The main Life Tables site has annual tables back to 1966 that show the increase in life expectancy over these years.